The present invention relates to an absorbent product, such as a sanitary napkin, comprising an absorbent body and a jacket enclosing said body, said jacket comprising a fluid-permeable layer located closest to the user when in use and a fluid-impermeable layer disposed on the opposite side--the back--of the absorbent body.
Leakage to the side has been a problem when using sanitary napkins. This has been a problem in all types of sanitary napkins, both the older types, i.e. thick and wide napkins, and in more modern types, e.g. so-called body-shaped napkins, which vary in thickness along their lengths and are relatively narrow in the midsection where they are thickest.
Sanitary napkins of the older, uniformly thick types are often greatly deformed when used quite simply because they are too large and not fitted to the shape of the human body. They also are not resilient and deform as the body of the wearer moves. Usually they are pressed together in the middle and bent along a longitudinal axis so that the front, the side in contact with the user, becomes convex with portions of the fluid-permeable layer facing out towards the sides at the same time as the fluid-impermeable back layer is more or less folded up resulting in a reduction in effective fluid-stopping surface. This means that fluid from the napkins can leak out through the folded out fluid-permeable front layer on both sides of the folded-up fluid-impermeable back layer. Leakage also is caused by the folding and shifting movement of the pad.
Attempts have been made to solve this problem by making the modern sanitary napkins so that when used they more closely follow the shape of the body and have their greatest absorption capacity where the need is greatest.
The modern sanitary napkins are not deformed especially much during use and are more comfortable. However, side leakage is still a substantial problem even in body-shaped napkins. On occasions when fluid discharge is great, experience has shown that not all the fluid has time to be absorbed; rather a portion can still leak out to the sides and over the longitudinal edges of the napkin.
Developments of the last few years, however, have made the napkins thinner and thinner. This has been made possible both by compressing the absorbent material, and by using high-absorbent material. Examples of such very thin and comfortable napkins are the thin sanitary pads with highly absorbent materials instead of sanitary napkins of the older thicker types.
For such thin napkins, side leakage is a problem as pads do not conform to the body. Since they are usually very thin, they must be relatively broad even in the middle, making them liable to be greatly deformed when used, unfortunately often resulting in edge leakage in this type of napkin as well.
Many different attempts have been made to eliminate the occurrence of lateral leakage. In thin napkins one example is to arrange a number of longitudinal compressed areas in the absorbent body for the purpose of rapidly spreading the fluid longitudinally. These compressed areas are, however, far from sufficient to satisfactorily eliminate edge leakage.
It is also known to further widen the fluid-impermeable back layer so as to cover, in addition to the back and side edges of the napkin, also a portion of the front side in contact with the user during use. In such a design the fluid already collected in the absorbent body is to be sure effectively enclosed, but instead there is the substantial disadvantage that the fluid-impermeable back layer folded in over the front side can cover a major portion of the napkin side facing the user when the napkin is deformed when used, whereby menstrual fluid can run directly out of the napkin on top of the portions of the back layer folded in over the front.
There have been proposed shaped pads for use as catamenial devices or incontinence use. European patent application No. 0091412--Widlund discloses a shaped pad. The pad of Widlund has elastic along the edges of the center portion of a generally rectangular pad. The elastic serves to shape the pad into a bowed shape with the elasticized edges extending upward beside the absorbent portion. Great Britain patent application No. 2,142,541--Buell discloses an elasticized waste containment garment, designed for incontinence use. This garment also has elasticized edges. In the Buell application the elastic extends almost the full length of the garment, and the elasticized edge portion not containing absorbent appears to be somewhat wider than that of Widlund. Another pad exhibiting elasticized edges is that disclosed in copending, coassigned application U.S. Ser. No. 629,297, Inventors Damico et al. titled "Bowed, Trough-Like Absorbent Pad."
There remains a need for a pad that fits the curve of the human body, is stationary during use, is comfortable to wear, effective, particularly against side leakage, and discreet. Thinner rectangular pads of the prior art are not of a shape that easily conforms to the body without bunching and being deformed. Therefore, there remains a need for an improved pad for catamenial use or for light incontinence use.